Pneumatic stapler device

ABSTRACT

A pneumatically operated stapler device is provided with a control valve appliance which enables single or repeated working strokes with adjustable sequence and which is operated by compressed air admitted by an air duct communicating the chamber of said control valve with an additional air chamber of the working cylinder.

United States Patent [56] References Cited UNITED STATES PATENTS3,278,103 10/1966 Juilfs et a1,

[72] Inventors Wilfried Lange 7 Brockhold, 3101 Altenhagen, Germany [21]AppLNo. 744,796

[22] Filed July 15,1968 [45] Patented Jan. 5, 1971 [32] Priority July13, 1967 I [33] Germany [54] PNEUMATIC STAPLER DEVICE 5 Claims, 2Drawing Figs.

[51] Int. F011 25/06 ABSTRACT: A pneumatically operated stapler deviceis pro- [50] Field 91/218 vided with a control valve appliance whichenables single or repeated working strokes with adjustable sequence andwhich is operated by compressed air admitted by an air duct commu- 308,304(Curs0 y), nicating the chamber of said control valve with anadditional 290(Cursory), cords air chamber of the working cylinder.

Cursory), 308, 304, 281, 290(Cursory), 220(Cursory), 291, 305, 293, 300,309(Cursory);

91/218(Cursory) 281(Cursory),

P n aims.

PATENTEDJAN 5:971 3,552,270

sum 1 OF 2 FIG! PNEUMATIC STAPLER DISCLOSURE OF THE INVENTION Thisinvention relates to a pneumatically operated stapler device,particularly for driving staples, nails and other fastener means into aworkpiece, with a control valve appliance to perform single orcontinuous working strokes. This control valve is hand-operated toconnect the working cylinder of the stapler with the compressed airsupply duct or with the open air, and is provided with an auxiliaryappliance for automatically repeating the working cycles which areinitiated by actuation of the control valve.

It is an object of this invention to provide a control valve applianceof the above-mentioned type to perform single and repeated workingstrokes.

Another object of the invention is to provide a simple and easilyadjustable auxiliary apparatus to control the sequence of percussionsperformed by the working cycle of the stapler device. 1

According to this invention, an additional chamber of the workingcylinder receiving compressed air for returning the piston to itsinitial position communicates, via an air port, with a valve chambercontaining the control valve in which valve chamber an auxiliary valvesubmitted to the pressure of an adjustable resilient force is providedfor the purpose of adjusting the sequence of the working cycles. Thisauxiliary valve permits an easy adjustment of the mode of operation ofthe device by a mere modification of the tension of its spring so thatthe device may be used in a simple manner either in intermittent or incontinuous operation or, alternatively, in one of the two modes ofoperation. The space required by this auxiliary valve is small and mayeasily be provided in the body of the device in the proximity of themanually actuated control valve.

Further objects and features of this invention are described withreference to the accompanying drawings.

In the drawings:

FIG. 1 shows in side elevation partly shown in section a stapling devicedriven by compressed air with an embodiment of the invention;

FIG. 2 shows, at a larger scale, the longitudinal section of the controlvalve appliance according to the invention in the position when thedevice is out of operation.

Referring to FIG. 1, the stapler device consists of a hollow housingbody 1 developed to form a handle which housing body 1 is provided, atits rear end, with a conduit 2 for a connection with a supply ofcompressed air (not shown). A compressed air reservoir 3 is arranged inthe housing body 1 and permanently connected to the compressed airsupply. The compressed air reservoir forms a storage chamber which, viaa control valve 4, communicates with a passage 5 leading to' the workingcylinder 6 arranged in the front part of the housing body 1. In thelatter, a piston 7 having a resilient bumper 60 is guided in knownmanner which'piston 7 actuates a driver 8 which separates the staplesfrom the magazine 9 arranged in the bottom of the housing body 1 anddrives them into the workpiece. During the working stroke of the piston7, the cylinder 6 is vented to the atmosphere through an exhaust outlet61 in the cylinder bottom and a lateral slot 62 in the nose of thedevice. The outlet 61 is sealed off by the bumper 60 when the piston 7reaches the end of its working stroke. Beneath the compressed airreservoir 3, a vent duct 10 is provided which, via the control valve 4,communicates with the passage 5 when, after the completion of itsworking stroke, the piston 7 is returned to its initial position asrepresented in FIG. 1.

As shown in detail in FIG. 2 the control valve 4 comprises asubstantially cylindrical valve housing 11 which, by means of a thread12, is screwed into a bore 13 of the housing body 1.

The control valve 4 is provided with a stepped valve body 14 slidablymounted on a release valve stem 16 provided with an axial bore 15. Thelower end of the release valve stem 16 is developed to form a pin 17which is provided with an operating element. for instance a finger tipplate 18.

The upper end of the valve housing 11 projects into the compressed airreservoir 3 and is provided with a port 19, through which the compressedair in the reservoir 3 acts on the upper face of the valve body 14. Atthe mouth of the passage 5, the valve housing 11 is provided, in twodiametrically opposed points, with a cutout 20 over which a shoulder 21is arranged which serves as a seat for an inlet valve. In normalposition as shown in FIG. 2, a sealing ring 22 arranged in a recess ofthe valve body 14 presses tightly against the shoulder 21 and therebyinterrupts the communication between the passage 5 and the compressedair reservoir 3. A valve seat 23 arranged below the cutout 20 is sealedby a sealing ring 24 which, in normal position, is raised from the valveseat 23 and thereby communicates, via a further cutout 25 of the valvehousing 11, the passage 5 with the vent duct 10.

The lower end of the valve body 14 is provided with a larger operativeface than the upper end permanently exposed to the action of thecompressed air. Against the enclosing cylindrical part of the valvehousing 11, this lower end is sealed by a sealing ring 26. Below thevalve body 14, a slide valve 27 of the same diameter as the lower end ofthe valve body 14 is slidably mounted on the release valve stem 16 and,against the latter, is sealed by a sealing ring 28, whereas, against theinner wall of the valve housing 11, it is sealed by a sealing ring 29.The slide valve 27 controls several ports 30 provided at the same radiallevel and communicating with an air passage 31. Furthermore, the slidevalve 27 is sealed, by an elastic disc 33, against the annular face atthe lower end of the valve body 14 which is provided with radial slits32. By cross bores 35 provided in the release valve stem 16, the valvehousing space 34 below the slide valve 27 is in open communication withthe axial bore 15 of the latter and, at its lower end, has an elasticbottom plate 37 which, like the bottom 38 of the valve housing 11, isprovided with a central cutout 39 of a larger diameter than the pin 17of the release valve stem 16.

In the initial position of the parts as shown in FIG. 2, an annularshoulder 36 of the release valve stem 16 seals the cutout 39. Beyondthis, in this position, the release valve stem 16 is slightly spacedfrom an elastic liner 41 arranged on the upper end wall 40 of the valvehousing 11 so that the compressed air in the air reservoir 3 can flowvia the axial bore 15 to the lower valve housing space 34 where it canact on the lower end of the slide valve v27. As the latter is providedwith a larger operative area than the upper end of the valve body 14permanently exposed to the action of the compressed air, the latter ispressed upwards into the position shown in FIG. 2 by the compressed airacting on the slide valve 27. In this position, the cutout 20 is closedagainst the compressed air reservoir 3 by the sealing ring 22 pressedagainst the inlet valve seat 21, and the passage 5 is in communicationwith the vent duct 10 via the opened valve seat 23.

The air passage 31 leading from the ports 30 in the lower part of thevalve housing 11 communicates with an auxiliary valve 42, thecylindrical housing 43 of which is arranged in a bore 44 of the housingbody 1 adjacent an additional chamber 45 of the working cylinder 6.Through two rows of ports 46 and 47 (of FIG. 1) this additional chamber45 receives the compressed air required to return the piston 7, aftercompletion of its working stroke, into its initial position shown inFIG. 1. The chamber 45 communicates with the auxiliary valve 42 by aport 48 provided in the upper part of the auxiliary valve housing 43 inwhich a valve piston 49 is slidably mounted under the action of acompression spring 51. The upper face of this valve piston 49 is conicalin shape and by the two 0- shaped rings 50 the piston is sealed againstthe inner wall of the auxiliary valve housing 43. At its upper end, thecompression spring 51 is enclosed by a tubular extension 52 of the valvepiston 49 and, at its lower end the spring 51 is enclosed by a sleeve53. The lower or opposite end of the spring 51 is supported by a hollowbolt 54 the axial bore 55 of which is in open communication with theopen air. A screw cap 56 is attached to the bolt 54 and is screwed on anexternal thread 57 of the auxiliary valve housing 43.

The operation of the control valve appliance is as follows:

For the execution of a working stroke of piston 7, the finger tip plate18 of control valve 4 is pressed upwards whereby the upper end of therelease valve stem 16 comes to rest against the elastic liner 41 andthus is closed against the compressed air reservoir 3. At the same time,the lower valve housing space 34 is vented, via the cutout 39, by therise of the annular shoulder 36. By the pressure of the compressed airfrom the compressed air reservoir 3 acting on its upper face, the valvebody 14 is moved downwards whereby the inlet valve 21 is opened and thevalve 23 leading to the vent duct is closed. Now, the compressed airflows, through the passage 5, to the upper face of piston 7 which makesits working stroke and, via the ejector slot, drives a staplefrom themagazine 9 into the workpiece.

At the end of the working stroke, the cylinder exhaust outlet 61 isclosed by the bumper 60 and the compressed air acting on piston 7 flows,through the upper narrow ports46, into the additional chamber 45 fromwhich it reaches, through the larger ports 47, the lower annular areabetween the bumper 60 and the bottom of piston 7 and returns the latterinto its initial position, as the bottom outlet 61 of the workingcylinder 6 is closed by the lower part of piston 7 and the cylinderspace over piston 7 is vented. I

Part of the compressed air which, at the end of the working stroke ofpiston 7, has penetrated into the additional chamber 45, flows, throughport 48, into the auxiliary valve housing 43 and acts on the conicaledge of the upper face of the auxiliary valve piston 49 submitted to theaction of the compression spring 51. When the initial tension 'of thecompression spring 51 adjusted by means of the screw cap 56, is overcomeby the pressure of the compressed air from the additional chamber 45acting on the auxiliary valve piston 49, the latter is moved downwardsand gives access to the air passage 31. This causes the compressed airto penetrate between the slide valve 27 and the lower end of valve body14 and to press the latter upwards so that the valve seat 21 is sealed.This causes the sealing ring 24 to be raised from its valve seat 23 sothat the compressed air over piston 7 may escape, through the passage 5and the opened cutout 25, into the atmosphere and the piston 7 regainsits initial position. As the pressure in the chamber 45 decreases uponreturn of the piston 7 to its initial position, the spring 51 causes thevalve piston 49 to return to its FIG. 2 position and the air passage 31is vented to the atmosphere through the interior of the auxiliary valvehousing 43 and the bore 55..

As, during the working stroke of piston 7, the lower valve housing space34 is vented and as, on the other hand, the compressed air from thereservoir 3 acting on the upper face of the valve body 14 is under ahigher pressure than the compressed air in the passage 31, the valvebody 14 is moved downwards and opens the inlet valve 21 so that freshcompressed air flows, through the passage 5, into the working cylinder 6and immediately acts on the piston 7 which had returned to its upper endposition so that the latter again makes its working stroke. This cycleis repeated until the operator releases the finger tip plate 18, thuscausing the cycle to terminate.

"By modifying the initial tension of compression spring 51 by means ofthe screw cap 56, the sequence of the working cycles of piston 7 may beadjusted to a large extent, the sequence of percussions, within acertain unit of time, being increased along with the decrease of theinitial tension of the compression spring 51. If, on the other hand, thescrew cap 56 is screwed further on to the thread 57 whereby the initialtension of the compression spring 51 is increased, the compressed airfrom the additional chamber 45 acting on the upper conical face of theauxiliary valve piston 49 can no longer move the auxiliary valve piston49 downward against the action of the strong'initial tension of thecompression springSl so that then the auxiliary valve 42 practicallybecomes ineffective and the deviceonly makes individualpercussionsinitiated, in each case, by the finger tip plate 18. By themere action of the screw cap 56, the percussion speed of the device maythus be controlled to a large extent for which purpose the screw cap x56 may be provided, on the outside,'with-a knurled surface as shownjnFIG. 1.

I claim:

1. In a pneumatically operated stapler device having a body cylinder andadapted to be driven in a working stroke froman initial position to aterminal position in said cylinderjthe improvement which comprises thecombination of?" an air chamber adjacent said cylinder, said cylinderhavinga wall with first port means for admitting compressedair from saidcylinder to said chamber after completion of said working strokeand'second port meansfor'admitting compressedair from said chamber tosaid cylinder for returning said workingpiston from said terminalposition to said initial position; control valve means regulating thepassage of compressed air from said reservoir to said cylinder andthe-venting of air from said cylinder, said controlvalve means'beingmanually operable for initiating operation of the device; air passagemeans communicating between said}; chamber and said control valve means;auxiliary valve means interposed in said air passage means andcomprising a valve housing, a valve piston movably disposed in saidvalve housing, spring means acting on one side of said valve piston, andadjustable means for regulating the spring force, and i said valvehousing having port means for subjecting the opposite side of said valvepiston to the air pressure in said chamber so as to admit compressed airfrom said chamber to said control valve means for a'c'tua'tihg'thelatter when' the air pressure in said chamber overcomes the force ofsaid spring, whereby to obtain automatic repetitive operation of thedevice, and said valve piston being nonresponsive to the air pressure insaid chamber in one position of said "adjustable means for obtainingnonautomatic operation of the device. 2. The device of claim 1 furthercharacterized in thatsaid control valve means comprises a movable valvebody arranged to regulate the passage of air from said reservoir to saidcylinder and the venting of said cylinder, and a shiftable slide, valvemember adapted to control the flow of air'through said. air passagemeans.

3. The device of claim 2 further characterized by the provision of amanually actuable tubular valve stem having said valve body and-saidslide valve member slidably mounted thereon, said valve stem in itsunactuated position providing fluid pressure communication between saidreservoir and said slide valve member for normally holding said valvebody, and said slide valve member in their. inoperative positions,andflsaid valve stem in its manually actuated positionpermitting'movement of said valve body and said slide valve member totheir operative positions in response to air pressure in said reservoir,said valve body being thereafter movable to its in'opera= tive positionaway from said slide valve member in response to air pressure in saidair passage means.

4. The device of claim 1 further characterized in that said 3 adjustablemeans comprises a screw cap having an adjustable threaded connectionwith said valve housing.

5. The device of claim 4 further characterized in that,said

screw cap is attached to a tubular element having an axial borecommunicating the interior of said valve housing with the.

open air, and said tubular element engages said spring for adjusting thecompression of the spring by manipulation of said screw cap.

1. In a pneumatically operated stapler device having a body with acompressed air reservoir, a working cylinder, and a working piston andstaple drive reciprocably disposed in said cylinder and adapted to bedriven in a working stroke from an initial position to a terminalposition in said cylinder; the improvement which comprises thecombination of: an air chamber adjacent said cylinder, said cylinderhaving a wall with first port means for admitting compressed air fromsaid cylinder to said chamber after completion of said working strokeand second port means for admitting compressed air from said chamber tosaid cylinder for returning said working piston from said terminalposition to said initial position; control valve means regulating thepassage of compressed air from said reservoir to said cylinder and theventing of air from said cylinder, said control valve means beingmanually operable for initiating operation of the device; air passagemeans communicating between said chamber and said control valve means;auxiliary valve means interposed in said air passage means andcomprising a valve housing, a valve piston movably disposed in saidvalve housing, spring means acting on one side of said valve piston, andadjustable means for regulating the spring force, and said valve housinghaving port means for subjecting the opposite side of said valve pistonto the air pressure in said chamber so as to admit compressed air fromsaid chamber to said control valve means for actuating the latter whenthe air pressure in said chamber overcomes the force of said spring,whereby to obtain automatic repetitive operation of the device, and saidvalve piston being nonresponsive to the air pressure in said chamber inone position of said adjustable means for obtaining nonautomaticoperation of the device.
 2. The device of claim 1 further characterizedin that said control valve means comprises a movable valve body arrangedto regulate the passage of air from said reservoir to said cylinder andthe venting of said cylinder, and a shiftable slide valve member adaptedto control the flow of air through said air passage means.
 3. The deviceof claim 2 further characterized by the provision of a manually actuabletubular valve stem having said valve body and said slide valve memberslidably mounted thereon, said valve stem in its unactuated positionproviding fluid pressure communication between said reservoir and saidslide valve member for normally holding said valve body and said slidevalve member in their inoperative positions, and said valve stem in itsmanually actuated position permitting movement of said valve body andsaid slide valve member to their operative positions in response to airpressure in said reservoir, said valve body being thereafter movable toits inoperative position away from said slide valve member in responseto air pressure in said air passage means.
 4. The device of claim 1further characterized in that said adjustable means comprises a screwcap having an adjustable threaded connection with said valve housing. 5.The device of claim 4 further characterized in that said screw cap isattached to a tubular element having an axial bore communicating theinterior of said valve housing with the open air, and said tubularelement engages said spring for adjusting the compression of the springby manipulation of said screw cap.